Electoral strategizing is, in fact, the main thing that there's reason to believe Perez will be non-trivially worse at.
How so? Over the course of the "campaign", Perez and Ellison held remarkably similar ideas on how the DNC should move forward and crafting messages across the country. Ellison focused on energizing the base more, sure, but Perez emphasized the importance of voter rights in this tumultuous time where they're in grave danger. Making sure people are able to vote is an important electoral strategy in my opinion.
It's also important to realize that the DNC chair might provide a vision for how the party should go, but the position is much more about fundraising and Sunday talk shows than anything else.